Recently, with the increase of Europeanization of dietary life, the demand for meat is increased and the products for supplying meat has desired a development of an efficient breeding method of domestic animals. The term "domestic animals" used throughout this disclosure will refer to those animals used for supplying meat and meat products for human consumption. The most important problem in stock-breeding is how to increase the production efficiency and hence the attempt of increasing the breeding density of domestic animals has been made but such an attempt rather deteriorates the breeding environment to frequently cause scours or a loose passage and thus make worse the growth of domestic animals. In particular, the inferior growth of young animals after weaning gives a large influence on the subsequent growth and the initial inferior growing period is greatly over the ordinary growing period of the animal to make worse the breeding efficiency and hence reduce the economical efficiency.
For the purpose of remedying the scours and loose passage of young animals, there is proposed a method of incorporating an antibiotic in a feed or a method in administering a large amount of an antibiotic, etc., for the treatment of a disease of domestic animals but the effect is not yet satisfactorily. On the other hand, for preventing the scours of domestic animals, the use of various lactic acid bacteria and L. bifidus solely or as a mixture of them is proposed (Japanese Patent Publication No. 47,907/'72 and Japanese Patent Publication (unexamined) Nos. 118,827/'76 and 9770/'80). Also, a method of applying various treatments to milk whey as a starting material and adding it to a feed for domestic animals for increasing the microorganisms existing in the alimentary canals of animals is proposed (Japanese Patent Publication No. 15,829/'79).
Some of the products industrially produced based on the above-described method are on the market and the effect is not yet satisfactorily and problems have been left at present for remedying the scours of domestic animals and efficiently increasing the weight of them.